feat: clear DataStore without first starting (aws-amplify#9768)

Co-authored-by: Jon Wire <[email protected]>

packages/datastore/__tests__/DataStore.ts

@@ -41,6 +41,20 @@ describe('DataStore observe, unmocked, with fake-indexeddb', () => {
 		await DataStore.clear();
 	});
 
+	test('clear without starting', async () => {
+		await DataStore.save(
+			new Model({
+				field1: 'Smurfs',
+				optionalField1: 'More Smurfs',
+				dateCreated: new Date().toISOString(),
+			})
+		);
+		expect(await DataStore.query(Model)).toHaveLength(1);
+		await DataStore.stop();
+		await DataStore.clear();
+		expect(await DataStore.query(Model)).toHaveLength(0);
+	});
+
 	test('subscribe to all models', async done => {
 		try {
 			const sub = DataStore.observe().subscribe(

packages/datastore/src/datastore/datastore.ts

@@ -1385,7 +1385,16 @@ class DataStore {
 
 	clear = async function clear() {
 		if (this.storage === undefined) {
-			return;
+			// connect to storage so that it can be cleared without fully starting DataStore
+			this.storage = new Storage(
+				schema,
+				namespaceResolver,
+				getModelConstructorByModelName,
+				modelInstanceCreator,
+				this.storageAdapter,
+				this.sessionId
+			);
+			await this.storage.init();
 		}
 
 		if (syncSubscription && !syncSubscription.closed) {